Impact of drought stress on seedling vigor and physio-biochemical attributes of diverse mungbean genotypes for drought tolerance through in vitro and field evaluation

Climate change threatens mungbean (Vigna radiata (L.) Wilczek) production disrupting crop growth and reducing yield. Therefore, developing climate resilient mungbean varieties is crucial for sustaining production. This research aims to evaluate the genetic variation for drought tolerance among 108 mungbean genotypes, including pre-breeding lines developed through distant hybridization, using in vitro screening (PEG6000@ − 0.5 MPa). Based on the seven seedling growth parameters under stress, 108 genotypes were grouped into four clusters. Twelve genotypes in the cluster IV were identified as drought tolerant showing higher mean for seedling growth parameters. The results were further confirmed independently. Four tolerant genotypes viz., VBN3, VBN4, COGG22-01 and VGG17-004 (SVI > 1165) and two susceptible genotypes, VGG16-047 and COGG17-02 (SVI < 230) were selected based on in vitro screening and subsequently validated under field condition (reproductive stage stress) using rainout shelter. Field evaluation revealed significant differences in the 12 morphological (leaf area, stomatal frequency), physiological (relative water content), biochemical (proline, soluble sugars) and yield determinants between tolerant and susceptible genotypes. The tolerant genotypes maintained higher relative water content (72.21–76.83%), reduced transpiration through altered stomatal and leaf traits and accumulated higher levels of proline (0.54–0.67 mg/g) and soluble sugars (19.56–24.12 mg/g dry weight) for osmoregulation. This adaptive response minimized the yield reduction under stress in tolerant genotypes. Drought tolerant genotypes, with relatively higher plot yield (141.21–166.93 g) under stress can be tested further in multilocation to assess their stability for yield and drought tolerance. The tolerant genotypes could be utilized as varieties or as potential donors for enhancing drought tolerance in mungbean.